Alright, here's the question. When you turn on the AC system, you're secondary fan should fire off right? Now, my ac has never worked, and I assumed it was because of a low/no freon situation. I never cared that much, figuring I'd get around to fixing it someday maybe. Once I installed the new electric water pump, I've been monitoring temps and messing around with a few ideas just for fun, and I figured I'd trigger the secondary fan at max cruising temp to see if the temps came down any, so I turned on the AC....no fan. Went home and jumpered for codes, both fans come on. By the way, I have the automatic climate control.

So, I'm wondering if the low freon condition could be not allowing the fan to come on, though I don't "think" that would be the case. The compressor never came on from the time I bought it, but it had a bared wire on the compressor harness, so I just unplugged it, figuring it was toast as well.

Anyway, I'm wondering if the bared wire could have shorted the relay, and maybe that's all I need.....

Thanks for any thoughts guys!

By the way, I did the "hold both fan buttons in, press middle button look for code" trick I found on the forum....no code, just double zero's

 

If the A/C is not working, then it won't "force" the cooling fan to come on.
Just turning on the a/c switch will not do it.

 

That's the part I'm wondering about. I've heard other members unplug their compressor and turn on the AC to run the secondary fan at the track, so I don't think the compressor not working would disallow fan opperation as normal. With the HVAC controls not throwing any "low freon / bad sensor" codes, I'm still in search of the probable culprit.

I'm still wondering if the bare wire on the compressor harness could have shorted the AC power relay.....which, by the way, I can't seem to locate. In my forum searches, I've seen other year models say they're located up under the dash, but that was on some of the l98 cars. Anyone know off the top of their heads where the AC power relay on the 92 LT1 is? Probably same place, since that's where I'd be if I wanted to make me look like a fool for asking the obvious

 

Your secondary fan is controlled by the ECM (Quad Driver 4), there is a A/C pressure sensor that has to be energized to allow the fan to turn on, thus if the compressor's not pumping, no fan.

There is no AC power relay but there is a compressor clutch relay in front of the battery.

You can wire in a manual switch to control the secondary fan, it's easy. But doing so will throw Code 28 (Quad Driver) because the Quad Driver monitors voltage in this circuit, not a big deal.

You relly can't do this stuff without an FSM.

 

Thanks for the info Bill. I thought for sure I'd read someone's post about unplugging the compressor and turning on the AC to get secondary fan control between passes at the track though. Ah well, probably a different year / set up.
You say the clutch control relay is in front of the battery.....I have two located there. Any Idea which one it is? I want to start testing the harness for power

 

Should be 4 relays there, bolted to the fender well just below the ECM.
Going from the drivers side to the pass side they are:

1-4 upshift

Secondary Fuel Injector 1

A/C clutch

Secondary Fuel Injector 2

But again note that while you will have power to the relay,the A/C pressure sensor won't allow the ECM to ground that relay and send power to the clutch. Just won't work without pressure.

 

nope, only have two that I see bolted to the inside of the fenderwell in front of the battery. I'm going out right now to see if I can locate any others!

 

This is a 92, right?

 

yepper, 1992